Multiple sclerosis (MS) is a chronic, frequently progressive, inflammatory central nervous system (CNS) disease characterized pathologically by primary demyelination, usually without initial axonal injury. The etiology and pathogenesis of MS are unknown. Several immunological features of MS, and its moderate association with certain major histocompatibility complex alleles, has prompted the speculation that MS is an immune-mediated disease.
An autoimmune hypothesis is supported by the experimental autoimmune (allergic) encephalomyelitis (EAE) model, where injection of certain myelin components into genetically susceptible animals leads to T cell-mediated CNS demyelination. However, specific autoantigens and pathogenic myelin-reactive T cells have not been definitively identified in the CNS of MS patients, nor is MS associated with other autoimmune diseases. An alternative hypothesis, based upon epidemiological data, is that an environmental factor, perhaps an unidentified virus, precipitates an inflammatory response in the CNS, which leads to either direct or indirect (“bystander”) myelin destruction, potentially with an induced autoimmune component. This hypothesis is supported by evidence that several naturally occurring viral infections, both in humans and animals, can cause demyelination. One commonly utilized experimental viral model is induced by Theiler's murine encephalomyelitis virus (TMEV) (Dal Canto, M. C., and Lipton, H. L., Am. J. Path., 88:497-500 (1977)).
The limited efficacy of current therapies for MS and other demyelinating diseases, has stimulated interest in novel therapies to ameliorate these diseases. However, due to the apparently complex etiopathogenesis of these diseases, potentially involving both environmental and autoimmune factors, the need still exists for an effective treatment of these demyelinating disorders.
rHIgM22 is a recombinant human IgM antibody that binds to mature oligodendrocytes and myelin of both rodents and humans, and promotes the synthesis of new myelin in in vivo models of demyelination. The standard dose of remyelination-promoting mAbs in prior studies has been 25 mg/kg, administered LP. This dose, if extrapolated to humans, would be impractical.
Accordingly, a need exists to develop a practical, safe and efficacious treatment regimen for CNS disorders, particularly those involving demyelination and/or remyelination, and it is toward the fulfillment of that need that the present invention is directed.
The citation of any reference herein should not be construed as an admission that such reference is available as “Prior Art” to the instant application.